High-water-pressure shield tunnel backfill grouting and duct piece floating model test device and method

The invention discloses a high-water-pressure shield tunnel backfill grouting and duct piece floating model test device and method. The device comprises a main body box, a tension system, a shield shell system, a ground stress loading system, a grouting system, a water injection system and a monitoring system. A shield shell system and model soil are contained in the main body box. The ground stress loading system and the water injection system are used for simulating underground complex soil and muddy water environments by applying stress and water pressure to model soil in the main body box. When the tension device enables the shield shell to advance forwards, the grouting system conducts grouting on the gap between the shield shell and the duct piece. A high-water-pressure shield tunnel wall back grouting visualization and duct piece floating integrated model test is achieved, and a shield tunnel and stratum multi-physical-field response rule under the high-water-pressure, complex and soft stratum environm